1. Field of the Invention
The present invention relates to an active matrix driven or passive matrix driven electro-optical apparatus such as a liquid crystal apparatus based on thin-film transistor driving or thin-film diode driving, a manufacturing method thereof, and an electronic device using the same.
2. Description of Related Art
A liquid crystal apparatus typically includes an electro-optical apparatus, a pair of alignment films that are rubbed in prescribed directions and provided on a pixel electrode and an opposing electrode between a pair of substrates, and an electro-optical material such as liquid crystal held between the alignment films. An electric field is applied to the electro-optical material from both electrodes. As a result, the alignment condition of the electro-optical material changes and a display is provided within an image display area.
Therefore, if a convex or concave portion caused by a difference in the total film thickness between an area comprising wiring lines (such as data lines, scanning lines and capacitor lines), driving circuits for driving pixels and the like such as thin-film transistor driving circuits (TFT) and thin-film diode elements (TFD) is left as it is up to a face (alignment film) in contact with the electro-optical material, then, defective alignment (disclination) may occur in the electro-optical material in response to the extent of convex or concave, which may lead to deterioration of the image for each pixel. More specifically, when an alignment film having an aperture area formed on the convex or concave face is rubbed, variations may occur in the alignment regulating ability on the alignment film surface in response to the extent of convex or concave. This may cause defective alignment of the electro-optical material and change the display contrast. Upon defective alignment of the electro-optical material for a normally white mode in which non-application of voltage onto the electro-optical material results in white display, a white dropout may occur at the position of defective alignment, which leads to a decrease in contrast which in turn leads to a decrease in fineness. In order to uniformly rub the alignment film over the entire substrate, a prescribed constant distance is maintained between the alignment films. To avoid this inconvenience, it is very important to flatten a pixel portion positioned within the image display area.
On the other hand, an electro-optical material may be sealed in a space surrounded by a sealing material between both substrates having wiring lines and driving circuits to form an electro-optical material layer. The sealing material may be an adhesive comprising a photosetting resin or a thermosetting resin for bonding both substrates around them. Particularly in a small-capacity electro-optical apparatus, the gap between the substrates may be controlled using a sealing material mixed with a bead-shaped or fiber-shaped gap material having an outside diameter of several μm. In the sealed area (i.e., area bonded by the sealing material), outgoing wire lines of the scanning and data lines are arranged from the image display area to the peripheral areas. This produces a step depending upon the presence or absence of the connecting lines. Such a step makes it difficult to gap control using the gap filler and stress concentration by the gap filler may cause breakage of lines or cause a short circuit. It is therefore very important to flatter the sealed area.